Oncolytic virotherapy is a bio-therapeutic platform for cancer treatment based on selective infection and killing of cancer cells by oncolytic viruses. Oncolytic viruses are replicating micro-organisms that show tissue tropism during infection of tumors and grow to increased levels in tumor cells relative to normal cells. Due to the enhanced viral burden in tumor cells (but not in normal cells) after infection, the cancer cells are subsequently killed by necrosis or apoptosis.
Some oncolytic viruses (both DNA and RNA viruses) have been identified to date, namely adenovirus, reovirus, herpes simplex virus (HSV), Newcastle disease virus (NDV), vaccinia virus, measles virus, coxsackievirus, and vesicular stomatitis virus (VSV).
While oncolytic viruses have been shown to be useful for cancer treatment, there is still a need in the art for the availability of additional oncolytic viruses. Having a repertoire of numerous oncolytic viruses with different modes of action, properties, and strategies to kill tumor cells of various tissue origins is desirable to thoroughly and effectively treat cancer. Identification of new oncolytic viruses is therefore useful to ensure the ability to efficiently target and kill a variety of tumors originating from various tissues. In addition, the combined use of different classes of oncolytic viruses for cancer therapy (multi-virotherapy) is an alternate route that can be much more efficacious in some cases than the use of a single virus class. The present invention satisfies this need in the art by providing methods of utilizing the newly identified oncolytic properties of respiratory syncytial virus (RSV) in various methods and compositions to treat cancer and related conditions.